Ch 7 study guide: Control of Microbial Growth Flashcards

1
Q

What does Sepsis refer to?

A

refers to bacterial
contamination (ex. septic tank)

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2
Q

What is Asepsis?

A

is the absence of
significant contamination

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3
Q

What is Sterilization?

A

removing and destroying
all microbial life

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4
Q

What is Commercial sterilization

A

killing
Clostridium botulinum endospores from
canned goods

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5
Q

What is Disinfection?

A

destroying harmful
microorganisms on a surface

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6
Q

What is Antisepsis?

A

destroying harmful
microorganisms from living tissue

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7
Q

How is sterilization distinct from the rest?

A

it removes and destroys ALL microbial life

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8
Q

Degerming

A

the mechanical removal of microbes from a limited area ex: alchohol swab

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9
Q

What is Sanitization?

A

lowering microbial counts on eating utensils to safe levels ex: dishwasher

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10
Q

whats a Biocide (germicide)?

A

treatments that kill microbes
- Fungicide: kills fungi
- Virucide: inactivates viruses

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11
Q

Bacteriostasis means..

A

inhibit growth and multiplication of microbes

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12
Q

What is particular about antisepsis?

A

It destroys harmful microorganisms from living tissue

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13
Q

Understand the shape of the microbial death curve.

A

More time that is exposed, more death occurs

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14
Q

What are the four factors that affect the control of the microbial death rate?

A
  1. Number of microbes
  2. Environmental influences
  3. Time of exposure
  4. characteristics of microbe
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15
Q

Which microorganism is the most resistant?

A

Prions

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16
Q

Which microorganism is the least resistant?

A

Viruses with lipid envelopes

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17
Q

does the presence of organic material affect most antimicrobial treatments?

A

The presence of organic matter often INHIBITS the action of chemical ANTImicrobials

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18
Q

What is the difference between dry heat and moist heat?

A
  • Dry heat kills by oxidation effects (ex: direct flame)
  • Moist heat coagulates/denatures proteins (ex: steam, autoclave, boiling, pasteurization)
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19
Q

Which type of heat is more effective at killing microorganisms? Why?

A

moist heat
it kills all organisms and endospores by denaturing their enzymes?

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20
Q

What are some examples of dry heat?

A
  • Direct flaming
    -Hot air sterilization (Oven)
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21
Q

What are some examples of moist heat?

A
  • Autoclave
  • Boiling
    -Pasteurization
22
Q

What are the standard conditions for autoclaving?

A
  • steam under pressure
  • 121C at 15psi for 15min
23
Q

How does how filtration acts to sterilize a solution?

A
  • High- efficiency particulate air (HEPA) filters remove microbes
24
Q

What is not effectively removed by filtration? (Two specific examples)

A
  • Flexible bacteria (spirochetes)
  • wall-less mycoplasma
25
Q

how does fast freezing (deep freezing) work? does it kill microbes?

A

mostly slows enzymes/ does not kill
(bacteriostasis)

26
Q

how does slow freezing work? does it kill microbes?

A

kills microbes
any water within bacteria will become crystals which disrupt cellular and molecular structure

27
Q

Radiation causes damage to which cellular macromolecule?

A

DNA (nucleic acids)

28
Q

What is a form of ionizing radiation?

A

x-rays, gamma rays, electron beams

29
Q

What is a form of nonionizing radiation?

A

ultraviolet, infrared (IR), microwave, 260nm

30
Q

Is microwaving an effective control of microbial growth?

A

Heck no

31
Q

Which physical methods are bacteriostatic?

A

heat, filtration, radiation, and the exposure to chemicals

32
Q

What is plasmolysis? Describe a condition where plasmolysis occurs

A

Plasmolysis is the process in which cells lose water which occurs in a hypertonic enviorment

33
Q

What is the mode of action for Alchohol

A

Denatures protein and can disrupt membranes

34
Q

What is the mode of action for Phenols

A

Injure lipids of plasma membranes, causing leakage

35
Q

What is the mode of action for Heavy metals and what are some examples?

A

Denature proteins, can be biocidal and antiseptic
ex: silver, mercury, copper, zinc chloride found in mouthwash

36
Q

What is the mode of action for Biguandies

A

Disrupt plasma membranes (especially gram-positive bacteria)

37
Q

What is the mode of action for Halogens

A

Impairs protein syntheses and alters cell membranes

38
Q

What is the mode of action for Surfactants

A

mechanical removal of microbes through scrubbing
Ex: hand scrubbing with soaps

39
Q

What is the mode of action for Oxidizing agents

A
40
Q

What are some examples of alcohols that can be used to kill microbes?

A

Ethanol and isopropanol, Purell, GermX

41
Q

What is the chemical in Lysol?

A

Phenol

42
Q

How do surfactants act to rid the body of microorganisms?

A

kills bacteria by interfering with and breaking up the cell membrane components such as lipids and proteins. Physically removed by scrubbings and rinsing

43
Q

What is the only example of a biguanide given in class?

A

Chlorhexidine used in surgical hand scrubs

44
Q

What are some examples of halogens?

A

Iodine, Chlorine

45
Q

What is the oldest and most effective chemical control agent?

A

Iodine

46
Q

What are some examples of heavy metals that kill microorganisms?

A

Silver, copper, Mercury, Zinc chloride is found in mouthwash

47
Q

What is the mode of action for Aldehydes?

A

Inactivate proteins by forming covalent cross links with several organic function groups on proteins

48
Q

Which chemicals act as sterilants?

A
  • peracetic acid
  • glutaraldehyde
49
Q

What three parts of the cell do various control agents target to kill or inhibit microbes?

A
  1. Plasma membrane (lysing cell)
  2. Proteins (enzymes)
  3. Nucleic acids (DNA/RNA)
50
Q

All of these are actions of microbial control EXCEPT
- Alteration of membrane permeability
- Damage to mictochondria
- Damage to proteins
-Damage to nucleic acids

A

Damage to mitochondria

51
Q

which chemicals act as sterilants?

A
  • peracetic acid
  • glutaraldehyde